The present invention relates to a constant-speed tripod joint of the type comprising a bell element provided with three pairs of tracks, the lines of the centers of which are curved, and a tripod element fixed axially inside the bell element, this tripod element comprising three arms each of which carries a roller which slides along the arm and is preferably rotatable about the axis of the arm. These joints are usually employed for driving the driving wheels of front-drive automobiles.
An object of the invention is to provide a constant-speed joint of this type, which has a high torque transmission capacity for a small volume and low weight and a high efficiency, even at large break angles.
The invention therefore provides a joint of the aforementioned type, wherein each roller is also mounted to pivot about a single axis which is parallel to or roughly parallel to the general axis of the tripod element.
Owing to this feature, the axial retention of the tripod element can be ensured solely by the bearing of the rollers against the edges of the tracks.
In an advantageous embodiment which ensures a very good guiding of the rollers, each roller has a toric rolling surface, each track having a corresponding toric surface which is bordered on the outer edge by a spherical region which is centered on the center of the bell element.
Preferably, in order to reduce risk of jamming, each track surrounds the corresponding roller at an angle of about 120.degree..